Film and cameras that are all in one, commonly referred to as single-use or one-time-use cameras, have become well known. The one-time-use camera is a simple point-and-shoot type comprising a plastic main body part which supports a conventional film cartridge in a cartridge receiving chamber, an unexposed film roll in a film supply chamber, a fixed-focus taking lens, a film metering mechanism with a rotatably supported metering sprocket that engages the filmstrip, a manually rotatable thumbwheel rotatably engaged with a film spool inside the film cartridge, a single-blade shutter, a manually depressible shutter release button, a rotatable frame counter for indicating the number of exposures remaining for picture-taking, a direct see-through viewfinder, and in some models an electronic flash. A pair of opaque plastic front and rear cover parts house the main body part between them to complete the camera. The rear cover part connects to the main body part and/or to the front cover part to make the main body part light-tight. A decorative cardboard outer box or label at least partially covers the camera and has respective openings for the taking lens, etc.
After each picture is taken with the one-time-use camera, the photographer manually rotates the thumbwheel in a film winding direction to similarly rotate the film spool inside the film cartridge. This winds an exposed section of the filmstrip into the film cartridge. The rewinding movement of the filmstrip the equivalent of slightly more than one frame width rotates the metering sprocket in engagement with the filmstrip to decrement the frame counter to its next lower-numbered setting and to pivot a metering lever into engagement with the thumbwheel in order to prevent -further manual rotation of the thumbwheel. Manually depressing the shutter release button to take another picture pivots the metering lever out of engagement with the thumbwheel to permit renewed rotation of the thumbwheel. When the maximum number of exposures available on the filmstrip are exposed, and the filmstrip is completely wound off the take-up spool and into the film cartridge, the one-time-use camera is given to a photofinisher who tears the outer box off the camera, separates the rear cover part from the main body part, and removes the film cartridge with the exposed filmstrip from the cartridge receiving chamber. Then, he removes the exposed filmstrip from the film cartridge to develop the negatives and make prints for the customer. At least some of the used parts of the camera may be recycled, i.e. reused, to remanufacture the camera.
It is suggested in prior art U.S. Pat. No. 5,353,165 issued Oct. 4, 1994 that the direct see-through viewfinder in the one-time-use camera be a single-piece transparent plastic construction comprising a pair of front and rear lens elements and an integral beam that interconnects the lens elements in a spaced optically aligned relation. The single-piece construction is formed in one molding process, which is supposed to reduce cost. However, a problem that may occur is that the front and rear lens elements can become displaced from their optically aligned relation during a cooling period following the molding process.
This problem appears to be possibly overcome in prior art U.S. Pat. No. 4,662,717 issued May 5, 1987. The patent discloses a two-piece viewfinder comprising a front lens element and a cylindrical barrel having an open front end an integral rear-end lens element. The front lens element and the open end of the cylindrical barrel are connected to one another to make a rigid cylindrical unit with the front and rear lens elements in a spaced optically aligned relation.